Evelia Schettini

Analysis and design of low-density polyethylene greenhouse films

In the present paper, the mechanical behaviour of low-density polyethylene (LDPE) films under various combinations of pre-tension and uniform pressure schemes is investigated experimentally and numerically using the finite element method of analysis. The behaviour of the film is simulated by means of numerical models and with the material properties obtained in the laboratory by using standard testing methods. The finite element models used include both a commercial finite element program and a recently developed research non-linear finite shell element, capable of modelling membrane behaviour. The numerical analysis results obtained under appropriate boundary conditions and different analysis options are compared with experimental results obtained from a specifically designed experimental arrangement. For the cases tested experimentally, the two numerical approaches gave results in a good agreement with the experiment results, in the linear elastic region. Subsequently, using the research finite element model, design criteria are developed for the reliable design of LDPE greenhouse films.

Agricultural plastic waste spatial estimation by Landsat 8 satellite images

Abstract The use of plastic materials in agriculture involves several benefits but it results in huge quantities of agricultural plastic waste to be disposed of. Input and output data on the use of plastics in agriculture are often difficult to obtain and poor waste management schemes have been developed. The present research aims to estimate and map agricultural plastic waste by using satellite images. Waste was evaluated by means of the indexes relating waste production to crop type and plastic application as defined by the land use map realized by classifying the Landsat 8 image. The image classification was carried out using Support Vector Machines (SVMs), and the accuracy assessment showed that the overall accuracy was 94.54% and the kappa coefficient equal to 0.934. Data on the plastic waste obtained by the satellite land use map were compared with the data obtained by using the institutional land use map; a difference of 1.74% was identified on the overall quantity of waste.

Georeferencing of agricultural plastic waste

The use of plastic materials in agriculture, for greenhouse covering, soil mulching, irrigation pipes, containers and bags, generates a huge amounts of plastic waste that must be properly disposed of. An adequate waste management and disposal system requires the knowledge of the waste generation on the land. This paper presents the results of a research, based on the application of a Geographical Information System, for mapping the waste generation in the municipality of Trinitapoli, Italy. Aim of the research is to identify the points of waste generation and to quantify the waste. A dedicated geo-referenced database with data on the spatial distribution and amount of the plastic wastes was created; waste density ranged from 3.3 kg ha-1yr-1 to 861 kg ha-1yr-1.

Biodegradable Spray Mulching and Nursery Pots: New Frontiers for Research

Agricultural activities need plastics for many applications such as films for soil mulching and pots for plants transplanting. The use of plastic products, made of fossil raw materials, such as polystyrene, polyethylene, and polypropylene results in huge quantities of plastic wastes to be disposed of. In the past two decades, the growing environmental awareness strongly encouraged researchers and industries toward the use of biodegradable polymers for solving the plastic waste problem. Researchers have made strong efforts to identify new biopolymers coming from renewable sources as valid ecosustainable alternatives to petroleum based plastic commodities. The main research results and current applications concerning the biodegradable plastics in agriculture, such as thermo-extruded Mater-Bi and sprayable water-born polysaccharides based coatings, are described in this chapter. A lineup of biopolymers coming from raw and renewable sources, such as polysaccharides, are reported; the intrinsic chemico-physical properties of polysaccharides, responsible for the realization of dry water stable hydrogels, suitable for the formation of both soil mulching coatings and transplanting biopots, are investigated. A description of the natural additives, fillers and cellulosic fibers included in the polymeric matrices, able to enhance the mechanical performance of coatings and pots is provided, together with the outputs in the specific applications.

Effect of hydrolyzed protein-based mulching coatings on the soil properties and productivity in a tunnel greenhouse crop system

Polymeric protein-based biocomposites were used in this work as water dispersions to generate, in situ, biobased mulching coatings by spray technique, as alternative to low density polyethylene films for soil mulching. At the end of their lifetime, these biodegradable coatings degrade in soil thank to the microbial community that mineralizes them. Protein hydrolysates (PH) were derived from waste products of the leather industry, while poly(ethylene glycol) diglycidyl ether (PEG) and epoxidized soybean oil (ESO) were used to make the biodegradable spray coatings. A study under greenhouse condition was carried out using seedling test plots in order to investigate the performance of the spray coatings and their possible influence on some aspects of leaf growth, functionality and nutritional quality of lettuce (Lactuca sativa L., Mortarella selection Romanella variety Duende) and on soil properties. The biodegradable coatings showed the same good agronomic performances comparable with the ones of a commercial low density polyethylene mulching film, maintaining the mulching effect for the requested cultivation period and ensuring at the same time a similar rate of plant growth and dry matter accumulation. The research showed that 2 months after the tillage carried out at the end of the cultivation the amount of coating residues present in the soil was <5% of the initial weight of the biodegradable coatings. At the end of the field test, the soil mulched with the polyethylene film recorded an electrical conductivity value lower with respect to the soil mulched with the sprayed coatings, which release nutrients in the soil during their decomposition.

Quantification of agricultural plastic waste for the determination of territorial indexes

The aim of the paper is the definition of territorial indexes to evaluate the quantity of agricultural plastic waste in a geographical region due to the main crop cultivations of that area. The local Authority of the Barletta, Andria, Trani Province, Italy, has shown interest to introduce modernization actions for the agricultural plastic waste management. The analysed territory is typically suited for vineyards, olive groves, and orchards. Several farms were examined by means of direct questions or compilation of questionnaires. Data gathered were elaborated in order to estimate territorial indexes as average values per year of the agricultural plastic waste quantities coming from different crops. The obtained results allowed to quantify the yearly generation of agricultural plastic waste as function of the typology.

Innovative sustainable strategies in agro-food systems and in buildings for energy efficiency

EU identified the energy efficiency policy as the major strategy for ensuring both the sustainability of the use of energy resources and to develop the transition towards a low-carbon and decentralized energy system in Europe. This paper presents a brief analysis on available innovative technologies to reduce the dependency of agriculture and agro-food sector from fossil energy, and comply with the international commitment to reduce greenhouse emissions and to combat climate change. A general overview is provided on the energy consumption in agriculture and agro-food sector, with particular focus on the Italian sector is taken into consideration. It is discussed the role of solid biomass in place of fossil resources and the application of solar cooling technology as new technologies for acclimatization in greenhouse agriculture. Moreover, the application of living vegetated horizontal and vertical layers on buildings is evaluated as innovative and natural technology for improving the sustainability of towns and reducing the energy consumption for air conditioning in summer and CO2 emissions in towns.

Biodegradable containers from green waste materials

Novel biodegradable polymeric materials based on protein hydrolysate (PH), derived from waste products of the leather industry, and poly(ethylene glycol) diglycidyl ether (PEG) or epoxidized soybean oil (ESO) were obtained and their physico-chemical properties and mechanical behaviour were evaluated. Different processing conditions and the introduction of fillers of natural origin, as saw dust and wood flour, were used to tailor the mechanical properties and the environmental durability of the product. The biodegradable products, which are almost completely manufactured from renewable-based raw materials, look promising for several applications, particularly in agriculture for the additional fertilizing action of PH or in packaging.